FI106004B - Extrusion procedure and extruder - Google Patents

Description

1 106004

Extrusion method and extruder

The present invention relates to an extrusion method, wherein the material to be extruded in the process is fed to an extruder having at least one stator and at least one rotor, wherein the stator is at least rotor-conical and at least stator-cone-shaped, a ratio of up to five times its maximum diameter, rotated by rotor 10 and bearing at its widest point in an extruder such that the rotor is rotated to rest on at least two bearings, the first bearing receiving a second axial force acting on the second rotor.

The invention further relates to an extruder having at least one stator and at least one rotor, the stator having at least a rotor face and a rotor having at least a stator face ratio of up to five times the maximum rotor length, and the rotor being mounted on an extruder. at least two bearings at their widest point, wherein the first bearing receives the forces in the second axial direction of the rotor, and. . t the second bearing receives the rotor in the opposite axial direction; . degenerate forces.

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; ; * Typically, the extruder has a length of screw that is quite large with its diameter of '' ·· ''. Long screw bearing is extremely difficult. No matter how hard the bearing of the 'i' is, at the other end, the screw can bend so much that it touches its outer cylinder, causing immediate rapid wear. A solution is shown and in which a long screw is also mounted on the nozzle-side end. ···. 30 so that the molten plastic flows through the bearing. This type of bearing prevents • ·. ···. bending of the screw, but resulting in very harmful joint seams in the plastic mass, which cause a weak point in the extruded product.

In order to produce products with a very slippery surface, a large amount of lubricant must be mixed with the 35 extrudable plastic masses. Large • ♦ t. however, the amount of lubricant insoluble in the plastic mass, such as silicone oil, causes • 2 106004 that the friction between the screw and the plastic mass is also small, so that the development of frictional heat is also low. The slight friction results in the mass slipping in the groove of the screw, sliding completely against the cylinder. However, as the plastic mass locks in place, a very strong bending moment is easily created on the screw 5. Thus, unexpectedly, the extremely slippery plastic mass of the type described above results in a situation where the wear of the screw is very strong and the bearing of the screw is necessary to support it.

DE-A-1 961 078 discloses an extruder having a cone-shaped stator and a second rotor of a cone mu-10 rotatably disposed thereon. The extrudable material is fed between the stator and the rotor. The rotatable rotor is supported by roller bearings from its outer periphery to the housing such that the roller bearings receive axially downwardly directed forces in the pattern. Further, the rotor is supported by rolling bearings which receive radial forces. This die-clamp cannot be utilized in a situation where an upward force is exerted on the rotor in the axial direction. Further, there is no way of observing the forces acting on the rotor, and consequently, of controlling and regulating those forces.

EP-A-89 906 779 discloses an extruder having at least 20 conical stators and at least two conical rotors interposed therebetween. The material to be compressed is fed through feed channels between the rotor and the stator. The rotors are mounted against a stator below the underside. This bearing receives downward forces, that is, when the pressure outside the rotor is greater than the pressure inside it. This bearing is not capable of absorbing upward or radial forces. Nor is it possible to observe and adjust the forces acting on the rotor.

CH Publication 525084 discloses an extruder with cylinders. 30 rotor shaped. The rotor is supported by two bearings to prevent • ·

The first bearing H1 receives the forces in the first axial direction and the second bearing the forces in the second axial direction.

** ί *: The cylindrical rotor bends quite easily, which increases the tolerance of wall thicknesses, for example when using lubricant, to 35. Further, the bearings provide sufficient support only in the axial direction, t <I <«'but not in the radial direction.

It is an object of the present invention to provide an extrusion method and an extruder in which the above-mentioned drawbacks do not occur.

The method according to the invention is characterized in that the bearings are arranged obliquely with respect to the axial and radial directions of the extruder, whereby the bearings together receive the forces acting in the radial direction.

Further, the extruder according to the invention is characterized in that the bearings are arranged obliquely with respect to the axial and radial directions of the extruder, whereby the bearings together receive the forces acting in the radial-10 direction.

In solving the problem, it has surprisingly been found that the sufficient length of the screw groove required to melt and homogenize the mass can be placed in a shorter screw shape if the screw itself is strongly conical. In this case, the length of the screw itself relative to its diameter-15 is made very short, which makes it possible to have an extremely sturdy bearing.

An essential idea of the invention is that the extruder comprises at least one conical stator and at least one conically rotatably arranged rotor and that the rotor is supported by at least two lower 20 rolls such that the lower bearing takes up the downwardly directed axial forces and the upward bearing . Another idea of the preferred embodiment is that the bearings are inclined axially and radially obliquely so that the bearings together receive radial force. In yet another preferred embodiment the idea is that the bearing assembly includes means for measuring the elastic displacement of the rotor, whereby this measurement is used to determine the forces acting on the rotor and the stator.

An advantage of the invention is that the bearing is made very sturdy, which also provides products with a high lubricant content. Southwest ···. By measuring the elastic displacement of the rotor, the extruder can be controlled • · y. '.' forces acting on time. The solution of the invention also allows to keep the wall tolerances of '*: ** products very low, ν': The invention will be explained in more detail in the accompanying figure, which shows: '' [: schematically seen from the side and in cross section.

The figure shows a side view of an extruder according to the invention, viewed in cross section. The extruder comprises an inner stator 1 and an outer stator 2 arranged on the outside thereof, at least the outer surface of the inner stator 1 and the inner surface of the outer stator 2 are conical. Between the inner stator 1 and the outer stator 2, a cone-shaped rotor 5 is arranged. The ratio of the length of the rotor 3 to the diameter of its widest point is at most five times greater. The rotor 3 is arranged to rotate between the inner stator 1 and the outer stator 2. The rotor 3 is rotated by a motor 5. The motor 5 may be, for example, a hydraulic motor or an electric motor, or another suitable motor known per se. The motor 5 is adapted to rotate the rotor 3 through a gearbox 4. By means of the transmission 4, the rotation speed of the rotor 3 can be adjusted as desired. On the other hand, for example, when using an electric motor, the gearbox 4 is not necessary, since the rotational speed of the rotor 3 can be easily controlled by adjusting the rotational speed of the motor 5 in a manner known per se. The components of the extruder described above are well known per se and are therefore not discussed further herein.

Further, the extruder is provided with a first feed channel 6 along which the material to be extruded can be fed outside the rotor 3 between the rotor 3 and the outer stator 2. Further, the extruder 20 includes a second supply channel 7 through which material can be fed into the interior of the rotor 3 through a hole or holes 8 in the rotor 3 between the rotor ... 3 and the inner stator 1. The first feed channel 6 is fed with feed material 9 by a first metering device 9. Similarly, a second feed device 10 is provided to feed the second feed channel 7. The metering devices 9 and 10 can be, for example, feed screws i or pumps or any other device known per se. By means of said '·' · [: metering device, the flow rate of the material to be fed to said feed channel is adjusted.

The rotor 3 is mounted on the gearbox body 11 by bearings 12a and 12b.

. ♦ ··. The bearings 12a and 12b are disposed so as to limit the movement ♦ ·. '• I of the rotor 3. in the direction of the extruder axis in each direction. The bearings 12a and T 12b may be, for example, plain bearings or ball bearings or some other similar bearings. Most preferably, the bearings 12a and 12b are conical; '; bearings, as shown in the figure below. The shafts of bearings 12a and 12b 35 shown in the figure below by a dashed line are most preferred.

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. min adapted to be obliquely in both the radial and axial direction of the extruder • · 106004. Thus, the upper bearing 12a receives the upwardly acting forces of the rotor 3 produced by feeding a second metering device 10 along the feed channel 7 through the holes 8 between the rotor 3 and the inner stator 1 with a greater material flow than the first metering device 9 along the feed 5 between. Otherwise, the lower bearing 12b receives the downward force of the rotor 3. The bearings 12a and 12b together receive the force acting in the radial direction on the rotor 3. Thus, the bearing arrangement in question provides a very sturdy bearing.

An upper clearance ring 13a is disposed between the gear housing 11 and the outer stator 2. Correspondingly, a lower clearance ring 13b is disposed between the inner stator 1 and the gear housing 11. The play rings 13a and 13b are interchangeable, thereby enabling the play between the rotor 3 and the stator 1 and 2 to be adjusted.

15 The outer stator 2, the gear housing 11 and the inner stator 1 are connected to each other by a fastening bolt 14. An upper measuring rod 15a and a lower measuring rod 15b are further attached to the gear housing 11. The upper measuring rod 15a is connected to the upper measuring sensor 16a and the lower measuring rod 15b is respectively connected to the lower measuring sensor 16b. The color rings 13a and 13b are, if necessary, able to flex slightly and, on the other hand, the fastening bolt 14 is also slightly stretched. Thus, the measuring transducers ... 16a and 16b are capable of detecting the elastic displacement of the measuring rods 15a and 15b and thus i; Y of the gearbox 11 and of the stator 1 and 2. Measuring sensors <»<; · 16a and 16b may be, for example, strain gauge sensors or other measuring devices fully known in the art. This elastic displacement is typically micrometers in height. The play rings 13a and 13b may also be spring-like, that is to say, they are relatively flexible, whereby the elastic displacement is also larger and thus easier to measure. Further, the load rings 13a and 13b may be provided with force sensors of which: · ♦ ·. 30 can directly obtain information affecting the play rings 13a and 13b

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the greatness of the forces.

• · '*: ** When the extruder is unloaded, the signal from measuring probes 16a and 16b can be set to zero. When the pressure 35 caused by the material fed between the rotor 3 and the outer stator 2 is greater than the pressure acting between the rotor 3 and the inner stator 1. they exert a force on the fastening bolt 14 which causes the fastening bolt 14 to be pulled. Thereby, for example, a positive signal Δδ1 is obtained from the upper measuring transducer 16a, which describes the elastic transfer work, which is thus proportional to the elongation of the fastening bolt 14, i.e. the force acting on it. At the same time, the gearbox body 11 is subjected to a downward force, whereby the lower measuring transducer 16b produces an elastic displacement work AS2 which can be defined as negative and thus proportional to the downward force acting on the gearbox body 11. Similarly, when the pressure between the rotor 3 and the inner stator 1 is greater than the pressure between the rotor 3 and the outer stator 2, the force exerted by the lower measuring transducer 16b and the upward force acting on the gearbox body 11 is obtained. defined by the upper measuring transducer 16a in this case with a negative signal representing the elastic transmission work Δ S1. Thus, the signals provided by the measuring sensors 16a and 16b are capable of accurately determining the forces acting on the extruder and, if necessary, adjusting the material flows of the materials fed to the extruder based on that measurement.

Because the bearing assembly in question is very robust and the process can be well controlled, the extruder according to the invention can even produce products in which at least 0.5% lubricant is blended with the material. The plastic matrix of the product can • ;. f is, for example, polyethylene or polyolefin and the lubricant is a silicone oil or a fluoroplastic compound. The product to be extruded may be, for example, a plastic tube or 1 i <; cable sheath or membrane or other similar product. The thickness tolerance of the product t 1 - '<25 can easily be less than 3%. Correspondingly, the tolerances for centering and diameter of the hole are also small.

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For example, by controlling the magnitude of the feed streams of the material to be compressed: T: Based on measurement of forces acting on the injection molding, it is possible to achieve a wall tolerance of less than 1%. On the other hand, by adjusting the solute ···. The amount of 30 solids in the material to be extruded is affected by the syringe. forces acting on the press. For example, a loose pulp can be fed to the outside of the rotor, and a rigid pulp can be fed to the inside and a lubricant can be fed to the inside of the pulp to be fed, whereby (<varying lubricant amount balances the forces acting on the extruder. «§ Add a substantially large amount of a standard lubricant, for example, more than 5%, for example a cable pipe which is easy to install inside the cable, i.e. the cable can be very long in the pull of such a product. By adjusting the glidant content to obtain controlled extruder forces, the device of the invention can even make products with high glidant content substantially without a joint seam.

The figure and the accompanying description are intended only to illustrate the idea of the invention. The details of the invention may vary within the scope of the claims. Thus, there may be more than two stators and more than one rotor, so that it is also possible to produce multi-layer products, for example. Further, there may be more than one measuring arrangement, for example preferably four, positioned at 90 ° intervals around the extruder, comparing the signals at each measuring location to provide information on the forces acting on the various extruder locations and adjusting extruder temperatures as needed to maintain product tolerances. a minimum. It is still possible to omit either of the stators from the extruder, whereby the material to be extruded is naturally only fed to one side of the rotor between the rotor and the stator.

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Claims (9)

8 106004 An extruding method, wherein the material to be extruded is fed to an extruder having at least one stator (1, 5 2) and at least one rotor (3), wherein the stator (1, 2) has a conical surface at least on the side of the rotor (3). (3) has at least a cone-shaped surface with a ratio of the length of the rotor (3) to its largest diameter not more than five times rotatable (3) and which is rotated (3) at its widest point to an extruder such that ) rotates on at least two bearings (12a, 12b), wherein the first bearing (12a) receives the force acting on the second axial direction of the rotor (3) and the second bearing (12b) receives the forces acting on the opposite axial direction of the rotor (3) (12a, 12b) are inclined obliquely with respect to the axial and radial directions of the die-15, the bearings (12a, 12b) collectively receive forces acting in the radial direction. Method according to claim 1, characterized in that the elastic displacement between the rotor (3) and the stator (1, 2) is measured and the forces acting on the extruder are determined on the basis of said measurement result. Method according to claim 1 or 2, characterized in that the extruder comprises at least two stator (1, 2), of which the inner stator (1) has at least its outer surface and the outer stator (2) has at least: , that there is at least one conical rotor (3) rotatably arranged between the stator (1, 2) and that the rotor (3) and the inner stator (1) as well as the rotor (3) and the outer one are measured separately. elastic transitions between the stator (2) and from these measurements the forces acting on the stator (1, 2) and the rotor (3) are determined. v A method according to claim 2 or 3, characterized in that a lubricant is added to the material to be fed between the stator (1, 2) and the rotor (3), the amount of the lubricant being adjusted based on the measurement result obtained from the elastic displacement. • · · Method according to Claim 3, characterized in that the material to be compressed is fed separately to the outside and inside 35 of the rotor (3) and that the amount of material to be fed to at least one side of the rotor (3) is controlled by the elastic displacement measurements. based on information available on 9 106004. An extruder having at least one stator (1, 2) and at least one rotor (3), the stator being at least on a rotor (3) side surface and the rotor (3) at least on a stator side surface conical with 5 rotors (3) the ratio of length to maximum diameter being up to five times, and each rotor (3) being mounted on the extruder by at least two bearings (12a, 12b) at its widest point, the first bearing (12a) receiving forces in the second axial direction of the rotor (3); receiving forces in the opposite direction of the rotor axial-10, characterized in that the bearings (12a, 12b) are arranged obliquely with respect to the axial and radial directions of the extruder, whereby the bearings (12a, 12b) collectively receive forces acting in the radial direction. Extruder according to Claim 6, characterized in that measuring means are arranged between the rotor (3) and the stator (1, 2) for measuring the elastic displacement between the rotor (3) and the stator (1, 2). Extruder according to claim 6 or 7, characterized in that the extruder has at least two stator (1, 2), of which the inner stator (1) is at least on its outer surface and the outer stator (2) is at least on its inner surface and 1, 2. there is at least one rotary cone (3) adapted to rotate and that the extruder comprises measuring means separately between the rotor (3) and: v. The outer stator (2) and the rotor (3) and the inner stator (1); to measure transitions. '' 'j Extruder according to one of Claims 6 to 8, characterized in that the bearings (12a, 12b) are conical bearings. ♦ * * • ♦ ♦ · • «· * i i i i 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 106 10 106004